This study is the first to date to uniquely characterize the prolonged use of RALs as primary access in postoperative neonatal and pediatric cardiac patients and to identify factors associated with RAL complications in this population. Our primary finding is that the incidence of RAL complications in our cohort was low. Compared to previous TTL studies, our rates of thrombosis and migration were similar while those of malfunction, infection, bleeding at removal, accidental removal and line retention were lower in our patient population. [2, 11] Similar to previous TTL studies that reported rates of thrombosis and migration ranging 0.4-4% [3, 5, 6, 9-11] and 1.2-5.3% [3, 6] respectively, our thrombosis and migration incidence reached 1.7% each. Our rates of RAL malfunction (1.4%) and infection (0.7%) were lower than previous series ranging 1.7-10.9% [2, 5, 8] and 1.1-8% [2, 5, 8-11] respectively. While no patient in our cohort underwent bleeding at RAL removal, accidental removal or line retention, the incidence of these complications in the current TTL literature reached 0.2-36%, [2-6, 7-10] 2.2-3.8%, [3, 8] and 0.07-0.7%, [3, 4, 6] respectively. These later findings could be related to our insertion and line securement techniques.
Interpreting TTL complication literature is challenging due to multiple factors. First, existing studies are very limited, and some were published decades ago, which challenges any longitudinal assessment of the data. Second, all the studies are retrospective reviews from single centers with different patient populations and study designs. Third, there are multiple discrepancies or lack in their complication definitions. For instance, bleeding at the time of TTL removal was defined varyingly across studies as increase in chest tube output, the need for a blood transfusion, hemodynamic compromise, the need for an intervention, the presence of a pericardial effusion on echocardiogram or tamponade physiology, which may account in part for the variability in the incidence of this specific complication. Furthermore, TTL are center specific with different indications, insertion techniques, monitoring, and protocols for removal, making interpretation of the current literature more conflicting. Table 5 summarizes the literature review. [2-6, 8-11]
Another factor to consider when interpreting complications is line duration. While historical TTL reports failed to provide clear data on line duration, [4-6] our study reported longer line duration than most recent reports. [2, 3, 8, 10, 11] Furthermore, 61% of our patients had their RAL removed at hospital discharge and 6 patients went home with the RAL in place for continuation of therapies. No increase in complications were observed with any of these practices in our patient population. This factor would be expected to portend worse outcomes to our patients since previous pediatric cardiac surgical studies like ours demonstrated that line duration (for both central venous lines and TTLs) is a significant predictor for line complications. [5, 11-14] Severity of illness could be an important confounding factor in this association since we tend to maintain central access longer in sicker patients and in those at risk for hemodynamic decompensation. Furthermore, the upper limit for line duration resulting in RAL complications continues to remain unknown and warrants more investigation.
We observed that palliation surgery was a significant factor for RAL complications in our cohort. As compared with other cardiac surgical patients, patients undergoing multistage single ventricle palliation have significant morbidity, extracardiac abnormalities and specifically anatomic complexities (such as heterotaxy syndrome) that could explain more RAL complications. [15, 16] They also tend to have increased severity of illness, leading to requirement of stable access for longer periods of time, which may also contribute to increased rates of complications. [15-17]
Over the last few decades, TTLs have played an increasingly important role in the postoperative management of pediatric cardiac surgical patients. While other centers use central venous lines and PICCs as fundamental access sites, we report the use of RALs as primary (and sometimes unique) access for the postoperative management of neonatal and pediatric cardiac patients. RALs seem to be a safe and essential tool with several undefined advantages. Vascular preservation of important vessels, particularly those utilized in single ventricle palliation pathways, is an important advantage to these lines. In a multi-institutional cohort study utilizing the Pediatric Cardiac Critical Care Consortium (PC4) registry, 31% of postcardiac surgical hospitalizations required a TTL. They reached 84% after Norwood operation and 56% after cavo-pulmonary connections. [11] Vessel patency ensures ongoing candidacy for palliative surgeries or transplant. [17] Access point reliability in extremely complicated and medically fragile patients is another benefit to these lines; particularly in the single ventricle population, who often have long postoperative courses with a high burden of morbidity requiring stable and durable access. The health of peripheral veins is also important for lifetime care in this and other cardiac patient populations. Furthermore, this access reliability minimizes morbidity and risks associated with subsequent anesthetic courses required to gain stable access when needed in these patients. [18-20]
Our study has a few limitations. First, it is a retrospective database review of a single-center experience with limited data. Second, we were not able to adjust for presumed factors associated with RAL complications such as severity of illness. Finally, a learning curve effect due to institutional procedural refinement may be an important confounder in the management of our patients.
In conclusion, the use of RALs as primary access site seems to be feasible and safe in the postoperative care of neonatal and pediatric cardiac patients. A prospective assessment of RAL complications as well as comparison with other types of central lines may improve outcomes in this patient population.